arXiv: High Energy Astrophysical Phenomena最新文献_第2页

Flipping spins in mass transferring binaries and origin of spin-orbit misalignment in binary black holes 传质双星的翻转自旋及双星黑洞自旋轨道偏差的成因

arXiv: High Energy Astrophysical Phenomena Pub Date : 2020-12-08 DOI: 10.1103/PHYSREVD.103.063007

Jakob Stegmann, F. Antonini

{"title":"Flipping spins in mass transferring binaries and origin of spin-orbit misalignment in binary black holes","authors":"Jakob Stegmann, F. Antonini","doi":"10.1103/PHYSREVD.103.063007","DOIUrl":"https://doi.org/10.1103/PHYSREVD.103.063007","url":null,"abstract":"Close stellar binaries are prone to undergo a phase of stable mass transfer in which a star loses mass to its companion. Assuming that the donor star loses mass along the instantaneous interstellar axis, we derive the orbit-averaged equations of motion describing the evolution of the donor rotational angular momentum vector (spin) which accompanies the transfer of mass. We consider: (i) a model in which the mass transfer rate is constant within each orbit and (ii) a phase-dependent rate in which all mass per orbit is lost at periapsis. In both cases, we find that the ejection of $gtrsim 30$ per cent of the donor's initial mass causes its spin to nearly flip onto the orbital plane of the binary, independently of the initial spin-orbit alignment. Moreover, we show that the spin flip due to mass transfer can easily dominate over tidal synchronisation in any giant stars and main-sequence stars with masses $sim1.5$ to $5,rm M_odot$. Finally, the general equations of motion, including tides, are used to evolve a realistic population of massive binary stars leading to the formation of binary black holes. Assuming that the stellar core and envelope are fully coupled, the resulting tilt of the first-born black hole reduces its spin projection onto the orbit normal by a factor $simmathcal{O}(0.1)$. This result supports previous studies in favour of an insignificant contribution to the effective spin projection, $chi_{rm eff}$, in binary black holes formed from the evolution of field binaries.","PeriodicalId":8437,"journal":{"name":"arXiv: High Energy Astrophysical Phenomena","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73215683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

The Thousand-Pulsar-Array programme on MeerKAT – II. Observing strategy for pulsar monitoring with subarrays MeerKAT - II上的千脉冲星阵列程序。脉冲星子阵监测的观测策略

arXiv: High Energy Astrophysical Phenomena Pub Date : 2020-12-07 DOI: 10.1093/mnras/staa3805

X. Song, P. Weltevrede, M. Keith, S. Johnston, A. Karastergiou, M. Bailes, E. Barr, S. Buchner, M. Geyer, B. Hugo, A. Jameson, A. Parthasarathy, D. Reardon, M. Serylak, R. Shannon, R. Spiewak, W. van Straten, V. Venkatraman Krishnan

{"title":"The Thousand-Pulsar-Array programme on MeerKAT – II. Observing strategy for pulsar monitoring with subarrays","authors":"X. Song, P. Weltevrede, M. Keith, S. Johnston, A. Karastergiou, M. Bailes, E. Barr, S. Buchner, M. Geyer, B. Hugo, A. Jameson, A. Parthasarathy, D. Reardon, M. Serylak, R. Shannon, R. Spiewak, W. van Straten, V. Venkatraman Krishnan","doi":"10.1093/mnras/staa3805","DOIUrl":"https://doi.org/10.1093/mnras/staa3805","url":null,"abstract":"The Thousand Pulsar Array (TPA) project currently monitors about 500 pulsars with the sensitive MeerKAT radio telescope by using subarrays to observe multiple sources simultaneously. Here we define the adopted observing strategy, which guarantees that each target is observed long enough to obtain a high fidelity pulse profile, thereby reaching a sufficient precision of a simple pulse shape parameter. This precision is estimated from the contribution of the system noise of the telescope, and the pulse-to-pulse variability of each pulsar, which we quantify under some simplifying assumptions. We test the assumptions and choice of model parameters using data from the MeerKAT 64-dish array, Lovell and Parkes telescopes. We demonstrate that the observing times derived from our method produce high fidelity pulse profiles that meet the needs of the TPA in studying pulse shape variability and pulsar timing. Our method can also be used to compare strategies for observing large numbers of pulsars with telescopes capable of forming multiple subarray configurations. We find that using two 32-dish MeerKAT subarrays is the most efficient strategy for the TPA project. We also find that the ability to observe in different array configurations will become increasingly important for large observing programmes using the Square Kilometre Array telescope.","PeriodicalId":8437,"journal":{"name":"arXiv: High Energy Astrophysical Phenomena","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80860106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Baikal-GVD: status and first results 贝加尔湖- gvd:现状和初步结果

arXiv: High Energy Astrophysical Phenomena Pub Date : 2020-12-06 DOI: 10.22323/1.390.0606

G. Safronov

引用次数: 7

Modeling a 2.5M⊙ compact star with quark matter 用夸克物质模拟2.5M⊙致密恒星

arXiv: High Energy Astrophysical Phenomena Pub Date : 2020-12-02 DOI: 10.1142/s0218271821500164

J. Horvath, P. Moraes

引用次数: 7

A semi-analytical treatment to wind accretion in neutron star supergiant high-mass X-ray binaries – I. Eccentric orbits 中子星超巨星高质量x射线双星中风吸积的半解析处理——偏心轨道

arXiv: High Energy Astrophysical Phenomena Pub Date : 2020-12-01 DOI: 10.1093/mnras/staa3761

E. Bozzo, L. Ducci, M. Falanga

{"title":"A semi-analytical treatment to wind accretion in neutron star supergiant high-mass X-ray binaries – I. Eccentric orbits","authors":"E. Bozzo, L. Ducci, M. Falanga","doi":"10.1093/mnras/staa3761","DOIUrl":"https://doi.org/10.1093/mnras/staa3761","url":null,"abstract":"We present in this paper a first step toward a semi-analytical treatment of the accretion process in wind-fed neutron star supergiant X-ray binaries with eccentric orbits. We consider the case of a spherically symmetric wind for the supergiant star and a simplified model for the accretion onto the compact object. A self-consistent calculation of the photoionization of the stellar wind by the X-rays from the accreting neutron star is included. This effect is convolved with the modulation of the mass accretion rate induced by the eccentric orbit to obtain the expected X-ray luminosity of a system along the orbit. As part of our results, we first show that the bi-modality of low and high X-ray luminosity solutions for supergiant X-ray binaries reported in previous papers is likely to result from the effect of the neutron star approaching first and then moving away from the companion (without coexisting simultaneously). We propose that episodes of strong wind photoionization can give rise to off-states of the sources. Our calculations are applied to the case of a few classical supergiant X-ray binary systems with known eccentricities (Vela X-1, 4U 1907+09, GX 301-2) and to the case of the only supergiant fast X-ray transient with a confirmed eccentric orbit, IGR J08408-4503. The results are compared with observational findings on these sources. We also discuss the next steps needed to expand the calculations toward a more comprehensive treatment in future publications.","PeriodicalId":8437,"journal":{"name":"arXiv: High Energy Astrophysical Phenomena","volume":"52 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85765511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Magnetic outflows from turbulent accretion disks 湍流吸积盘的磁流出

arXiv: High Energy Astrophysical Phenomena Pub Date : 2020-11-30 DOI: 10.1051/0004-6361/202039322

J. Jacquemin-Ide, G. Lesur, J. Ferreira

{"title":"Magnetic outflows from turbulent accretion disks","authors":"J. Jacquemin-Ide, G. Lesur, J. Ferreira","doi":"10.1051/0004-6361/202039322","DOIUrl":"https://doi.org/10.1051/0004-6361/202039322","url":null,"abstract":"Astrophysical disks are likely embedded in an ambient vertical magnetic field. This ambient field is known to drive magneto-rotational turbulence in the disk bulk but is also responsible for the launching of magnetized outflows at the origin of astrophysical jets. The vertical structure and long-term (secular) evolution of such a system lack quantitative predictions. It is nevertheless this secular evolution that is proposed to explain time variability in many accreting systems such as X-ray binaries. We compute and analyze global 3D ideal-MHD simulations of an accretion disk threaded by a large-scale magnetic field. We evaluate the role of the turbulent terms in the equilibrium of the system. We then compute the transport of mass, angular momentum, and magnetic fields in the disk to characterize its secular evolution. We perform a parameter survey to characterize the influence of disk properties on secular transport. We find that weakly magnetized disks drive jets that carry away a small fraction of the disk angular momentum. The mass-weighted accretion speed remains subsonic although, there is always an upper turbulent atmospheric region where transonic accretion takes place. We show that a strongly magnetized version of the magneto-rotational instability drives this turbulence. The disk structure is drastically different from the conventional hydrostatic picture. The magnetic field is always dragged inwards in the disk, at a velocity that increases with the disk magnetization. Beyond a threshold on the latter, the disk undergoes a profound radial readjustment. It leads to the formation of an inner accretion-ejection region with a supersonic mass-weighted accretion speed and where the magnetic field distribution becomes steady, near equipartition with the thermal pressure. This inner structure shares many properties with the Jet Emitting Disk model described by Ferreira (1997).","PeriodicalId":8437,"journal":{"name":"arXiv: High Energy Astrophysical Phenomena","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84854474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

AstroSat view of IGR J17091−3624 and GRS 1915 + 105: decoding the ‘pulse’ in the ‘Heartbeat State’ AstroSat对IGR J17091−3624和GRS 1915 + 105的观测:解码“心跳状态”中的“脉冲”

arXiv: High Energy Astrophysical Phenomena Pub Date : 2020-11-26 DOI: 10.1093/mnras/staa3756

T. Katoch, Blessy E. Baby, A. Nandi, V. K. Agrawal, H. M. Antia, K. Mukerjee

{"title":"AstroSat view of IGR J17091−3624 and GRS 1915 + 105: decoding the ‘pulse’ in the ‘Heartbeat State’","authors":"T. Katoch, Blessy E. Baby, A. Nandi, V. K. Agrawal, H. M. Antia, K. Mukerjee","doi":"10.1093/mnras/staa3756","DOIUrl":"https://doi.org/10.1093/mnras/staa3756","url":null,"abstract":"IGR J17091--3624 is a transient galactic black hole which has a distinct quasi-periodic variability known as `heartbeat', similar to the one observed in GRS 1915+105. In this paper, we report the results of $sim 125$ ks textit{AstroSat} observations of this source during the 2016 outburst. For the first time a double peaked QPO (DPQ) is detected in a few time segments of this source with a difference of $delta f ~sim12$ mHz between the two peaks. The nature of the DPQ was studied based on hardness ratios and using the static as well as the dynamic power spectrum. Additionally, a low frequency (25--48 mHz) `heartbeat' single peak QPO (SPQ) was observed at different intervals of time along with harmonics ($50-95$ mHz). Broadband spectra in the range $0.7-23$ keV, obtained with textit{SXT} and textit{LAXPC}, could be fitted well with combination of a thermal Comptonisation and a multicolour disc component model. During textit{AstroSat} observation, the source was in the Soft-Intermediate State (SIMS) as observed with textit{Swift/XRT}. We present a comparative study of the `heartbeat' state variability in IGR J17091--3624 with GRS 1915+105. Significant difference in the timing properties is observed although spectral parameters ($Gammasim2.1-2.4$ and $T_mathrm{max}sim0.6-0.8$ keV) in the broad energy band remain similar. Spectral properties of segments exhibiting SPQ and DPQ are further studied using simple phase resolved spectroscopy which does not show a significant difference. Based on the model parameters, we obtain the maximum ratio of mass accretion rate in GRS 1915+105 to that in IGR J17091--3624 as $sim25:1$. We discuss the implications of our findings and comment on the physical origin of these exotic variabilities.","PeriodicalId":8437,"journal":{"name":"arXiv: High Energy Astrophysical Phenomena","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83688834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

X-ray flux in SED modelling: An application of X-CIGALE in the XMM-XXL field x射线通量在SED模型中的应用:X-CIGALE在XMM-XXL领域的应用

arXiv: High Energy Astrophysical Phenomena Pub Date : 2020-11-18 DOI: 10.1051/0004-6361/202039401

G. Mountrichas, V. Buat, Guang Yang, M. Boquien, Denis, Burgarella, L. Ciesla

{"title":"X-ray flux in SED modelling: An application of X-CIGALE in the XMM-XXL field","authors":"G. Mountrichas, V. Buat, Guang Yang, M. Boquien, Denis, Burgarella, L. Ciesla","doi":"10.1051/0004-6361/202039401","DOIUrl":"https://doi.org/10.1051/0004-6361/202039401","url":null,"abstract":"X-CIGALE, built upon the spectral energy distribution (SED) code of CIGALE, implements important new features: The code accounts for obscuring material in the polars of the AGN and has the ability to fit X-ray fluxes. In this work, we use ~2500 spectroscopic, X-ray AGN from the XMM-XXL-North field and examine the improvements the new features bring in the SED modelling analysis. Based on our results, X-CIGALE successfully connects the X-ray with the UV luminosity in the whole range spanned by our sample (log Lx(2-10 keV) = (42 - 46) erg/s). The addition of the new features globally improves the efficiency of X-CIGALE in the estimation and characterization of the AGN component. The classification into type 1 and type 2 based on their inclination angle is improved, especially at redshifts lower than 1. The statistical significance of the AGN fraction, fracAGN, measurements is increased, in particular for luminous X-ray sources (log LX > 45 erg/s). These conclusions hold under the condition that (mid-) IR photometry is available in the SED fitting process. The addition of polar dust increases the AGN fraction and the efficiency of the SED decomposition to detect AGN among X-ray selected sources. X-CIGALE estimates a strong AGN (fracAGN > 0.3) in more than 90% of the infrared selected AGN and 75% of X-ray detected AGN not selected by IR colour criteria. The latter drops to ~50% when polar dust is not included. The ability of X-CIGALE to include X-ray information in the SED fitting process can be instrumental in the optimal exploitation of the wealth of data that current (eROSITA) and future (ATHENA) missions will provide us.","PeriodicalId":8437,"journal":{"name":"arXiv: High Energy Astrophysical Phenomena","volume":"417 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91449513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Heat release in accreting neutron stars 吸积中子星的热释放

arXiv: High Energy Astrophysical Phenomena Pub Date : 2020-11-18 DOI: 10.1103/PhysRevD.103.L101301

M. Gusakov, A. Chugunov

引用次数: 3

On the behavior of the black hole candidate 1E 1740 .7‐2942's corona based on long‐term INTEGRAL database 基于长期INTEGRAL数据库的候选黑洞1E 17400.7‐2942日冕的行为

arXiv: High Energy Astrophysical Phenomena Pub Date : 2020-11-18 DOI: 10.1002/ASNA.202113926

P. Stecchini, Jurandi Leao, M. Castro, F. D’Amico

{"title":"On the behavior of the black hole candidate\u0000 1E 1740\u0000 .7‐2942's corona based on long‐term\u0000 INTEGRAL\u0000 database","authors":"P. Stecchini, Jurandi Leao, M. Castro, F. D’Amico","doi":"10.1002/ASNA.202113926","DOIUrl":"https://doi.org/10.1002/ASNA.202113926","url":null,"abstract":"One of the most straightforward ways to explain the hard X-ray spectra observed in X-ray binaries is to assume that comptonization of soft photons from the accretion disk is occurring. The region where this process takes place, called the corona, is characterized by only two parameters: its thermal energy $kT$ and its optical depth $tau$. Hard X-ray spectra analysis is, thus, an imperative tool in diagnosing the behavior of these parameters. The lack of consistency in obtaining/analysing long-term databases, however, may have been hindering this kind of characterization from being attained. With the aim of better understanding the corona behavior in the black hole candidate 1E 1740.7-2942, we performed a homogeneous analysis for a large hard X-ray data set from the ISGRI telescope on-board the INTEGRAL satellite. Results from modelling the spectra show that, for most of our sample, unsaturated thermal comptonization is the main mechanism responsible for the hard X-ray spectra observed in 1E 1740.7-2942. Moreover, such extensive database allowed us to produce what is probably the longest hard X-ray light curve of 1E 1740.7-2942 and whose units -- due to recent findings regarding dynamical quantities of the system -- could be expressed in % of Eddington's luminosity.","PeriodicalId":8437,"journal":{"name":"arXiv: High Energy Astrophysical Phenomena","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83262299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0